Influence of Sb content on carrier transport and thermoelectric properties of flexible Bi–Sb films

In this study, the Bi–Sb films with different Sb content on silicon and polyimide (PI) substrates were successfully fabricated via high vacuum magnetron sputtering and the carrier transport and thermoelectric properties were studied. As the Sb content increased, the carrier concentration, electrical conductivity, Seebeck coefficient, and power factor of deposited Bi–Sb films initially increased and then decreased at room temperature. The maximum Seebeck coefficient and power factor reached −108.90 μV K−1 and 0.133mW m−1 K−2 for the Bi84Sb16 film at room temperature. The electrical conductivity, Seebeck coefficient, and power factor of deposited Bi–Sb films increased with increasing energy gap. Whether bending toward or bending back toward, the relative electrical conductivity of the films decreased with increasing bending angle. When the bending angle was less than 90°, the electrical conductivity of the films decreased very little. However, the electrical conductivity of the films exhibited an obvious reduction when the bending angle exceeded 90°. The relative electrical conductivity of the deposited films under bending toward and bending back toward decreased by 4% and 8% under 180° bending angle, respectively. Compared with bending toward, the electrical conductivity of the films bending back toward (tensile) decreases even more at the same bending angle. The electrical conductivity of the films bending toward changed little and remained 94.1% after bending 1000 times at the radius of 3 mm. The maximum power density of a flexible thermoelectric generator for Bi84Sb16 film was 0.672 and 0.8644 W m−2 at ΔT = 30 and 39 K, respectively.